TALI
FIGUEROA: Discovering
dark matter is going to be one of the greatest finds of the century.

NEIL
deGRASSE TYSON: Also...

MARGIE
PETERS (Alzheimer Patient Tillie
Venear's Daughter): Do you
remember who these people are?

NEIL
deGRASSE TYSON: For many of us,
holding onto even the most precious memories is impossible.

MARGIE
PETERS: These are your
great-grandchildren.

TILLIE
VENEAR (Alzheimer's Patient):
Really?

NEIL
deGRASSE TYSON: But new research
indicates there may be hope.

ERIC
LANDER (The Broad Institute of M.I.T and
Harvard): ...that memories can
be stored, apparently lost, and then regained.

NEIL
deGRASSE TYSON: And these swimming
lab mice may hold the clue.

LI-HUEI
TSAI (Massachusetts Institute of
Technology): They can find the
platform much faster.

NEIL
deGRASSE TYSON: Their brains have
been experimentally rewired to help them recover a lost memory: how to swim to
safety.

PETER
STANDRING (Correspondent): And when you realized that, what did you think?

LI-HUEI
TSAI: I
was overjoyed.

ERIC
LANDER: I think that these experiments are just plain amazing. They tell us
that there's so much more potential in situations where we might have
given up all hope.

NEIL
deGRASSE TYSON: And in the digital
age, how do we know if the pictures we see are real or fake?

Here's
a Harley-riding computer scientist who thinks he has the answer.

HANY
FARID (Dartmouth College): Think forensics, the way you would think CSI
forensics, but now it's pixels instead of hair.

NEIL
deGRASSE TYSON: He's a
digital detective who spends most of his time creating fakes and forgeries.

HANY
FARID: When I'm creating a forgery, it's a
little like being an artist.

NEIL
deGRASSE TYSON: In our profile, art
meets science in the interest of putting the real phonies out of business.

HANY
FARID: I'll be able to create fakes, but you won't.

NEIL
deGRASSE TYSON: All that and more,
on this episode of NOVA scienceNOW.

Funding for NOVA scienceNOW is provided by:

Americans are living
longer, spending more on health care. At Pfizer we're working on ways to
help with medicines that help prevent illnesses, with programs that provide our
medicines to people without coverage, and new partnerships that keep costs down
and keep people healthy. Pfizer: Working together for a healthier world.

And by the National Science
Foundation, where discoveries begin. And...

And the Alfred P. Sloan
Foundation, to portray the lives of men and women engaged in scientific and
technological pursuit.

And the George D. Smith Fund.

And by PBS viewers like you. Thank you.

DARK MATTER

NEIL
deGRASSE TYSON: Hi. I'm Neil
deGrasse Tyson. Welcome to a new season of NOVA scienceNOW.

Now,
I'm an ordinary guy, and that means, of course, I'm made up of
ordinary matter: basically, atoms. And when we gaze out into space, everything
we see—galaxies, stars—is also ordinary, made of atoms.

But
a lot of scientists say there's something else in the universe
that's NOT ordinary.

Wait,
who said that?

NEIL'S
JACKET SLEEVE: And by the way, there seems
to be way more of this weird stuff than ordinary guys like you...

NEIL
deGRASSE TYSON: Hey, watch it!

And
even though it's invisible, it's getting harder and harder to
ignore.

Every
day, a crew squeezes into an 80-year-old elevator in Minnesota and commutes to
work a half a mile down, into the depths of an abandoned mine.

They're
not searching for gold or diamonds. Instead, they're mining for something
even more coveted and harder to find, something called dark matter.

RICHARD
MASSEY: Dark matter is one of the biggest
mysteries.

TALI
FIGUEROA: Dark matter is
everywhere.

RICHARD
MASSEY: We wouldn't be here if it
weren't for the dark matter. Life wouldn't be possible.

TALI
FIGUEROA: The problem is
we have no clue what the dark matter is.

JOCELYN
MONROE (Massachusetts Institute of
Technology): We know it's
out there, and we just have to find it.

NEIL
deGRASSE TYSON: One of the people
now trying to find dark matter is physicist Tali Figueroa.

TALI
FIGUEROA: Discovering
dark matter is going to be one of the greatest finds of the century.

NEIL
deGRASSE TYSON: So, they really
mine iron in this place.

His
search takes place a half-mile under ground, where this old iron mine has been
transformed into a cavernous, space-age physics lab.

When
I visited, I didn't notice any dark matter, but I did see quite a bit of
dead matter.

Whoa,
what is this thing?

TALI
FIGUEROA: That's a
bat.

NEIL
deGRASSE TYSON: It doesn't
look very alive.

TALI
FIGUEROA: Probably isn't.

NEIL
deGRASSE TYSON: Whoa, there's
one there...another, another.

TALI
FIGUEROA: They're
all over the place.

NEIL
deGRASSE TYSON: That's nasty.

TALI
FIGUEROA: It is, kind
of.

NEIL
deGRASSE TYSON: Nasty. So that
doesn't creep you out?

TALI
FIGUEROA: You get used
to it.

NEIL
deGRASSE TYSON: Down here,
surrounded by the dead bats, Tali and his colleagues monitor and care for a
complex contraption specially designed to detect particles of dark matter.

So
this is it, huh?

TALI
FIGUEROA: Yup.

NEIL
deGRASSE TYSON: This elaborate
endeavor is all to solve a mystery that's been plaguing astrophysicists
for more than 70 years.

It
might seem bizarre and even a bit crazy, but there's a chance that most
of the matter in the universe is not stars or planets or gas or anything familiar
to us, but is in the form of some mysterious invisible substance. We've
labeled it "dark matter," but why do we think it exists at all?

It
comes down to gravity and speed. Ever since Isaac Newton, we've known
that it's gravity that holds objects in orbit, just as the sun holds
Earth and the rest of the planets.

The
stronger the gravity pulling it inward, the faster an object can go and stay in
orbit. It's kind of like spinning a heavy ball around: the harder you
pull on the ball, the faster the ball will travel. If the ball gets moving too
fast, even a strong guy like this has got to let go.

PETER
FISHER (Massachusetts Institute of
Technology): The faster you want
something to go—like, you know, David throwing his slingshot—the
more you have to pull on it. And the thing that's pulling on something to
make it orbit is gravity.

NEIL
deGRASSE TYSON: And where does
gravity come from? Well, we know it can be things with mass like stars, houses,
planets, trains, clouds, jellyfish; they all have gravity.

So,
in the universe, the more stuff, the more gravity, and the faster objects can
move and remain in their orbits. The problem is when we look out beyond our
solar system, like at stars orbiting within galaxies, or galaxies moving within
galaxy clusters. They're all orbiting faster than we'd expect.

JOCELYN
MONROE: The speed at which the stars are
going around at is too fast. You would expect that it should just escape, but
those stars don't escape. They're still going around.

NEIL
deGRASSE TYSON: There's got
to be a lot of gravity holding them all together, but apparently there's
not enough matter to account for it.

PETER
FISHER: And
there's not enough stuff. There's just not enough stuff to keep
them all going around each other.

NEIL
deGRASSE TYSON: Regardless of how
we probe the cosmos for this missing matter—using visible light, radio
waves, x-rays—we still come up short. Either we've got the laws of
gravity completely wrong, or there's got to be more stuff. Actually, we'd
need about five times more stuff. It's stuff we can't see, but what
exactly is it?

RICHARD
MASSEY: What is dark matter?

MAX
TEGMARK (Massachusetts Institute of
Technology): What is the dark
matter?

RICHARD
MASSEY: Yeah, that is a big question.

TALI
FIGUEROA: We don't
know what it is.

RICHARD
MASSEY: It's completely invisible.

TALI
FIGUEROA: It's
dark. It doesn't glow.

MAX
TEGMARK: So,
whatever the dark matter is...

TALI
FIGUEROA: We can't
point a telescope up and actually see it.

MAX
TEGMARK: ...it
sure ain't made of atoms.

NEIL
deGRASSE TYSON: Everything around
us that we can see and touch, ordinary matter, is made of atoms. But one thing
we know is dark matter is not ordinary.

RICHARD
MASSEY: We know its not ordinary matter,
because ordinary matter has all this whole other variety of interactions. It
has electric fields and magnetic fields. It emits light.

NEIL
deGRASSE TYSON: One idea is, since
it's not made of ordinary atoms, dark matter might be made of some exotic
particle. Right now, physicists around the world are racing to build a detector
sensitive enough to capture one, so they can figure out exactly what it is.

But
how do you catch a particle that's so shy?

TALI
FIGUEROA: The
fundamental problem is that this dark matter does not interact with matter very
much. And so, in order to detect it, we have to build these really specialized,
very sensitive detectors.

NEIL
deGRASSE TYSON: At this underground
lab, Tali Figueroa is monitoring one kind of dark matter detector, a
superconducting crystal made from the element germanium.

So,
one of your detectors, huh?

TALI
FIGUEROA: Yes, this is a
prototype of one of the 30 detectors. And when you look at the surface of our
detector, you'll see a metal grid.

NEIL
deGRASSE TYSON: The grid picks up
tiny temperature changes, produced when a particle hits the crystal and sets
all its atoms vibrating. But to detect those vibrations, the atoms in the
crystal have to start out as still as possible, something atoms don't
normally like to do.

TALI
FIGUEROA: The problem is
that naturally, at room temperature, the atoms are vibrating themselves.

NEIL
deGRASSE TYSON: So, how does the
team manage to slow down the detector's atoms? They put it in a freezer,
a very powerful freezer.

So
the whole point of this is to simply keep the experiment cold?

TALI
FIGUEROA: Yes. We have
to keep the experiment at about 50 milliKelvin, which is 50/1000 of a degree
above absolute zero.

NEIL
deGRASSE TYSON: Just a fraction of
a degree above absolute zero? Translated into Fahrenheit, that's, like,
460 degrees below zero. So, in other words, it's cold enough so that the
air we breathe freezes solid.

TALI
FIGUEROA: Absolutely.

NEIL
deGRASSE TYSON: And so
there's frost everywhere.

But
now there's another problem. The frozen detector is so hyper-sensitive,
lots of things could set it off, like cosmic rays, particles that shower Earth
from space. So this is why the whole lab is deep under ground.

So
the bedrock...

TALI
FIGUEROA: The half a
mile of rock...

NEIL
deGRASSE TYSON: ...above...

TALI
FIGUEROA: ...is a
shield.

NEIL
deGRASSE TYSON: ...is a shield. So
the cosmic rays...these are high energy particles from space?

TALI
FIGUEROA: From space.

NEIL
deGRASSE TYSON: Okay. So
you're protecting yourself from space.

And
it's not just cosmic rays. Even under ground, there are other tiny
particles flitting around us, including photons and neutrons that can fly out
of the surrounding rock. So the detectors are cloaked in layer upon layer of
shielding, all in an effort to filter out everything but the dark matter. And
how are things going so far?

Okay,
how many dark matter particles have you found so far?

TALI
FIGUEROA: None.

NEIL
deGRASSE TYSON: None?

TALI
FIGUEROA: None.

NEIL
deGRASSE TYSON: It's not too
surprising. The quest for dark matter here on Earth has only just begun, and
bigger and more sensitive detectors are already in the works. Still, you might
wonder, could it be that dark matter is something that's just out there
in space and not down here with us?

Astrophysicist
Richard Massey says, "not likely." He's got the first-ever,
3-D dark matter maps to back him up. But how do you map the unseeable?

RICHARD
MASSEY: So we can't see dark matter
directly; it's completely invisible. But we can work out where it is by
its effects on the ordinary matter that we can see.

NEIL
deGRASSE TYSON: In other words, you
can see dark matter's gravity. That's because, according to
Einstein and nearly a century of experiments, what gravity does in the universe
is bend space. Massive objects like the sun actually bend and stretch the
contours of space. That's what keeps smaller objects, like Earth, in
orbit.

And
if space is bent, so is any light that passes through it.

RICHARD
MASSEY: So let's debunk the whole
idea that light travels in straight lines. Light travels in what it thinks are
straight lines. And because space is warped and bent, even the straight lines
that light rays travel along are actually bent themselves.

NEIL
deGRASSE TYSON: The phenomenon is
called gravitational lensing. Think of what a thick magnifying glass can do the
text of a book.

RICHARD
MASSEY: When we put a magnifying glass in
front of it, we start seeing a distorted image, and gravitational lensing to
find dark matter works in a very similar way.

NEIL
deGRASSE TYSON: A huge clump of
dark matter and the enormous gravity it creates would bend areas of space so
much, it would act like a giant cosmic lens, distorting our view of distant
galaxies.

The
more distortion, the more gravity, and, Massey assumes, the more dark matter
lies between them and us.

RICHARD
MASSEY: So, the final result is that we
end up having this map of where the dark matter is in the universe.

NEIL
deGRASSE TYSON: Maps such as these
are now revealing that galaxies like ours are completely enveloped by giant
clouds of dark matter.

RICHARD
MASSEY: Wherever there's ordinary
matter, so even here, there is some dark matter. It's everywhere. The two
really have gone together, hand in hand.

NEIL
deGRASSE TYSON: In fact, as the universe
evolved after the Big Bang, dark matter may have served as a kind of
cosmological glue that, over time, helped pull stars together to form galaxies.

RICHARD
MASSEY: We owe everything to dark matter,
in two ways: firstly, it holds the whole universe together; but then it also,
crucially...inside that, it forms this scaffolding in which the ordinary matter
can lay to grow.

MAX
TEGMARK: We are so
lucky to have dark matter, because we wouldn't even be here otherwise. It
was the gravitational attraction from dark matter that pulled together this
diffused gas that eventually formed our Milky Way galaxy that we live in. And
if there were no dark matter, then our galaxy would, in fact, never have
formed.

NEIL
deGRASSE TYSON: If that's
true, then it's not just our Milky Way. Across the universe, none of the
billions of galaxies out there would have formed without the gravity of this
mysterious stuff.

Now,
we just need to find out what it is.

MAX
TEGMARK: It's
really astonishing that there's five times more stuff out there than we
know of, and that we've been at this, as a community, for over 70 years. And
yet it might be now, in the next few years, that we'll figure it all out.
It's just incredible.

OF MICE AND MEMORY

NEIL
deGRASSE TYSON: For most of us, a
stroll down Memory Lane is an easy trip.

There's
a good one.

But
for the tens of millions suffering from memory loss, like those with
Alzheimer's disease, it's different.

In
some cases, memory might still be there, but the pathways in our brain that
give us access to those memories might be broken or blocked, leaving the
memories out of reach.

But
what if your brain could build new pathways to lost memories?

As
correspondent Peter Standring reports, some new research shows that someday
that might just be possible.

MARGIE
PETERS: People always said
that she was the life of the party. She was very energetic. She was well known
in her circle as a dancer, and she was just a bubbly, exuberant young woman.

Do
you remember who these folks are?

PETER STANDRING: Tillie Venear is 84.

TILLIE
VENEAR: Zachary?
No.

MARGIE
PETERS: These are your
great-grandchildren.

TILLIE
VENEAR: Really?

PETER STANDRING: Until a few years ago,
Tillie was living a comfortable life, retired in Florida. But then she started
having trouble with her memory.

MARGIE
PETERS: She had a car
accident. Then she got a ticket for going while a school bus was stopped. Then
there was another car accident, and I started thinking, "I don't
know if she's safe down there."

PETER STANDRING: Doctors said Tillie
probably had Alzheimer's. She moved to an assisted living facility, but
her memory just got worse and worse.

MARGIE
PETERS: One day, they called
and said, "Your mother's standing in her room with her pants in her
hands, not knowing what to do with them." And then she started staying in
bed all day and staying in her room more. Finally, one day, the phone call
came. They found her in the stairwell crying, sitting there saying, "Where
am I? Where am I going?"

PETER STANDRING: Alzheimer's was
robbing Tillie of, not only her memories, but also her personality. Her family
moved her out of assisted living to a new nursing home, and suddenly, they
noticed a surprising change.

MARGIE
PETERS: But this very loving,
bubbly, almost girlishness, has emerged since she's been here. She became
involved again. She sort of sparked a little bit more. Her exuberance came
back.

PETER STANDRING: Somehow, putting Tillie
in a new place brought back parts of her personality that seemed like they were
gone forever. How is that possible?

When
patients like Tillie regain function or seem to get their memories back, even
for a short period of time, it provides clues to an amazing idea: maybe
memories aren't totally lost, maybe they can be restored.

At
MIT, these mice may help us find memories that are buried in our brains.

So,
Dr. Tsai, what room is this that we're in now?

LI-HUEI
TSAI: So, this is a room where we test the behaviors of
mice.

PETER STANDRING: And what have we got
here? I'm sure this is not a hot-tub.

This
tub of water is a way to test learning and memory.

LI-HUEI
TSAI: You can see we fill up the tank about halfway with
murky water, so when you place the mouse in the tank it cannot see through. And
then we place a platform that's submerged underneath the surface of the
water.

PETER STANDRING: Now don't worry,
the mice know how to swim, so what they have to do is learn where the platform
is and climb onto it.

They
practice for just 90 seconds at a time, a few times a day, and pretty soon they
figure it out. And once they get the hang of it, they always remember where
they can find the safe haven.

But
after they've learned the route, Tsai gives them a toxic protein that
destroys brain cells, and when she puts them back in the water, the mice forget
where the platform is and have to be rescued.

So
this mouse's brain is, basically, not functioning properly.

LI-HUEI
TSAI: No, no, no. If the mouse, after vigorous training,
still cannot find the platform, it clearly is impaired in their learning
ability and cognitive function.

PETER STANDRING: Tsai wanted to find out,
could those lost memories be restored? So after they're nice and dry, the
mice get a treat.

What
is this, Dr. Tsai? I'm assuming that it's not necessarily a
playground for the mice?

LI-HUEI
TSAI: Well, this is a Disney World for the mice.

PETER STANDRING: This experiment tests
something that has been studied for many years but never really understood.
It's called "environmental enrichment."

LI-HUEI
TSAI: If you keep rodents in a very rich environment, with
lots of toys, and house them in groups with lots of companions, then somehow,
they become smarter.

PETER STANDRING: After just a short
vacation at Disney World, Tsai puts the mice back in the water,
and—here's the surprise—amazingly, they swim straight to the
platform.

So,
after a few weeks in Disney World, they go back into the water maze, and
they're able to find the platform?

There's
a possible clue in the work of neuroscientist David Sweatt. His hobby is
painting abstract images of the brain cells he studies in his lab.

J. DAVID SWEATT (University
of Alabama at Birmingham): The work
that's going on in the laboratory, and in neuroscience in general, right
now, is the most interesting thing in the world. So, that's what I need
to paint.

PETER STANDRING: Sweatt lost his mother
to Alzheimer's, and now he's trying to figure out new ways of
understanding how brain cells create memories.

His
search starts deep inside neurons, where long strands of DNA are tightly coiled
around a group of proteins called "histones."

DAVID
SWEATT: It's as if
you were winding sewing thread on a spool. The histones are kind of like the
spool, and the DNA is wrapped around the histones like a few wraps of thread
around a spool.

PETER STANDRING: Analyzing brain cells
from normal mice, Sweatt discovered that when DNA is wrapped tightly around the
histones, genes are hidden, but when the DNA loosens up, genes involved in
learning and memory are exposed and can be switched on.

And
as that happens, the brain cells appear to be making more and stronger
connections with each other. This was a new pathway into the creation of
memories that had never been understood before.

DAVID
SWEATT: When you have a
new process like that, you can think of new, entirely new and different ways to
go about attacking the problem of memory dysfunction.

PETER STANDRING: Back at MIT, Li Huei
Tsai had also discovered something new. The mice's stay in Disney World
seemed to have sparked the same process, even in their impaired brains. Their
DNA was also loosening up and making memory genes more active. And somehow,
even though they'd lost a significant number of neurons, this was helping
their cells make new connections, essentially rewiring the remaining neurons so
their brains could work better.

LI-HUEI
TSAI: We found that even though these mice have fewer
neurons, each neuron seems to be more effective.

PETER STANDRING: What are the processes
that are happening to allow this sort of rewiring?

LI-HUEI
TSAI: That's a very important question. Because if
we understand that, then you can imagine that one day maybe it's possible
to have a pill that we all can take, and that will have this magical effect.

PETER STANDRING: A pill that could bring
back memories? Well, it may not be so farfetched. Sweatt's lab has
already studied a group of experimental drugs called HDAC inhibitors—the
h stands for histones—that are involved in loosening up DNA in brain
cells. And when the drugs are given to normal mice, they learn and remember
better.

So
Tsai decided to see if they would have any effect on her mice with damaged
brain cells. She took a new group of forgetful mice and gave them the
experimental drugs. And, within a short time, they also remembered how to swim
straight to the platform.

LI-HUEI
TSAI: We found that the HDAC inhibitors drastically
improved the learning ability of our mouse model.

PETER STANDRING: And when you realized
that, what did you think?

LI-HUEI
TSAI: I was overjoyed.

ERIC
LANDER: What's so interesting about what Li-Heui Tsai has shown, is that
memories can be stored, apparently lost, and then regained. By taking that
mouse and either giving it an enriched environment or certain drugs, she can
show that those mice can recover some of those memories.

PETER STANDRING: There is no way to know
whether these new discoveries will ever apply to humans or lead to treatments
for memory disorders. But for now, they're a tantalizing insight and a
new direction for more research into the mysteries of memory.

ERIC
KANDEL (Columbia University): This is such a profound problem. And it is of such
enormous significance because it effects the most fundamental aspects of our
character, our personality, of who we are, that any advance is a step forward.

ERIC
LANDER: I think these experiments are just plain amazing. They tell us what the
potential is, that there's so much more potential in situations where we
might have given up all hope.

PETER STANDRING: There aren't any
drugs to reverse the effects of Alzheimer's in humans, but Tsai's
experiments may help explain something families have known for a long time: the
more stimulating the environment, the better patients like Tillie usually do.

MARGIE
PETERS: ...going to feed the
birds, okay? One, two, three.

PETER
STANDRING: Her new nursing home is
centered on a philosophy of care called the "Eden Alternative,"
with a special program to give Alzheimer's patients as much stimulation
as they can manage.

ATTENDANT: Let's have a wonderful lunch together.

WALTER
COLLINS (Briarwood Healthcare & Rehabilitation Center):
Everything that we try to do is resident-
or person-centered, to empower those people with dementia to make decisions to
the extent that they can...

ATTENDANT
What are you going to have?

TILLIE
VENEAR: I'll
have meatloaf.

WALTER
COLLINS: ...and to provide a loving home
for them, which is what they deserve.

ATTENDANT
After we make the cookies, Tillie, what do we do? We
put the music on and we...what?

TILLIE
VENEAR: We
dance!

PETER STANDRING: Tillie is thriving in
this enriched environment.

MARGIE
PETERS: She's made this
place her own, and made her life here her own. She just became happy again.

PROFILE: HANY FARID

NEIL
deGRASSE TYSON: They say a picture
is worth a thousand words, but what if those words are just lies?

With
digital technology, anybody can appear to be or do just about anything. So what
do we do when seeing is no longer believing? When it's gotten harder to
tell fact from forgery?

Well,
in this episode's profile, you'll meet a scientist who's
developing the forensic tools to recognize a fake when he sees it.

Hany
Farid is 42 years old, and spends much of his time making fakes and forgeries,
images that are meant to trick the human eye.

HANY
FARID: When I am creating a forgery, it is a little bit
like being an artist. You have to think about, well, the colors and the palettes,
and the lighting and the contrasts, and all the various things that artists
probably think about.

I
find it really fascinating to try to create these visual fakes. I think it's
interesting, purely from an aesthetic and artistic point of view.

NEIL
deGRASSE TYSON: But Hany is not a
forger or a crook. He's a Dartmouth College computer science professor
who likes taking chances. He rides a Harley.

HANY
FARID: There's something really exciting and risky
and slightly dangerous about it. I wouldn't give it up for anything.

NEIL
deGRASSE TYSON: And Hany is
anything but predictable.

HANY
FARID: So on any given morning, I might take a shower,
brush my teeth, shave, get dressed and leave. And on another day, I'll
shave, shower, brush my teeth. Or I'll brush my teeth, shower and shave. Or
I'll brush my teeth, have my coffee, and then go back and do it. What
happens is that when I fall into a routine, I think my thinking falls into a
routine.

NEIL
deGRASSE TYSON: Thinking is his
obsession.

HANY
FARID: You have to wake up and you have to go to sleep
thinking, thinking about the problem and turning it around and spinning it.

So
everywhere I go, I have a pad of paper and a pen.

NEIL
deGRASSE TYSON: What he's
thinking about is something called digital forensics, an entirely new field
that Hany helped pioneer.

HANY
FARID: The basic idea is... I mean, think forensics the way
you would think CSI forensics, but now it's pixels instead
of hair.

NEIL
deGRASSE TYSON: As a digital
detective, Hany takes what he learns from making forgeries...

HANY
FARID: So imagine you're somebody who is trying to
catch a counterfeiter. How do you learn? How do you learn how to detect that? Well,
you have to know how they do it.

NEIL
deGRASSE TYSON: ...and he creates
powerful software. When he runs that software on a photograph, he can show if
it's real or fake. Like this Time Magazine cover of O.J. Simpson, well
known to have been manipulated.

HANY
FARID: I think we do want to believe what we see; it's
our first reaction. I, however, think that is changing. More and more, when
people see photographs that are fantastic, there is an initial, "Oh, how
do we know it hasn't been Photoshopped?"

The
reality is that photographs have been manipulated since the 1800s, since the
start of photography, actually. So you're talking about something that's
been going on for hundreds of years. And if you look throughout history, in
fact, all the great dictators doctored photographs to change history. Stalin
did it, Mussolini, Castro, Mao. I mean they all manipulated photographs.

NEIL
deGRASSE TYSON: In the digital age,
we're flooded with images, and the problem of the tampered photograph has
only gotten worse.

Hany
and his team of graduate students have joined forces with the FBI and other law
enforcement agencies, but how can they beat the forgers?

HANY
FARID: Most of what we think about is authentication. Can
you show that something has been added to the image? Has it been removed from
the image? Has this person been airbrushed? Is it somebody else's head on
somebody else's body? So think about all the types of digital fakes you've
seen: you know, the guy holding the really big cat, the really big hogzilla. On
all those things, we ask the question, "Is this a legitimate photograph?"

NEIL
deGRASSE TYSON: They approach it
like a detective would.

MICAH
K. JOHNSON (Dartmouth College): In a sense, images contain natural fingerprints. So
we build tools that can detect these fingerprints.

HANY
FARID: One of the most common ways of manipulating a photograph
is to remove something or somebody from a photograph. And the most common way
to do that is to typically take one part of an image, copy it and paste it into
another part of the image to hide that person or that object. And when you do
that, you've left behind a very specific statistical trace. You've
left behind two regions that are virtually identical.

NEIL
deGRASSE TYSON: And that process is
called cloning.

HANY
FARID: Probably the most famous example of cloning was the
photograph that Reuters published that came out of Lebanon after an Israeli
strike. It showed smoke billowing out of a building.

NEIL
deGRASSE TYSON: To Hany, something
about the smoke looked unnatural. But how could he confirm his suspicions?

Hany
created software that detects identical pixel patterns.

HANY
FARID: So we've developed a very efficient algorithm
that can detect whether two parts of an image are identical. We call this the
anti-cloning tool. The software analyzes it, and what comes back is a
color-coded image that says all of these pixels which we color-code in red, for
example, are the same as all of these pixels which were color-coded blue. So
there are these two highlighted areas. It's very distinct, and it's
very recognizable.

NEIL
deGRASSE TYSON: Hany's software
confirmed that the photographer had digitally added more smoke after the photo
was taken. Portions of the image had been cloned.

Hany
was able to develop his next technique, thanks to the budding relationship of
Brad Pitt and Angelina Jolie, in 2005.

HANY
FARID: This is when they were still rumored to have a
relationship, and everybody was dying to get that photograph of them together.

NEIL
deGRASSE TYSON: So was this
infamous photo real or fake? Hany could see with his own eyes that something was
very wrong. His clues were the light and the shadows.

HANY
FARID: Interestingly, by the way, most people don't
notice it. They look at the image, two beautiful people. Who cares, right,
where the light was? It doesn't matter to us.

NEIL
deGRASSE TYSON: Just by looking,
Hany could tell it was a fake.

HANY
FARID: The light was off by a good 120 to 130 degrees. It
was completely opposite directions. So for Brad Pitt the light was on his left,
and for Angelina Jolie, the light was on her right.

NEIL
deGRASSE TYSON: Which means there
were two separate photographs made to look like one.

HANY
FARID: So that made us think, well, this would really be a
really cool digital forensics tool. What if we could estimate, from an image,
where the light was?

NEIL
deGRASSE TYSON: Thanks to
"Brangelina," Hany used linear algebra and physics to develop his
light-direction software. It can tell you where the light came from when the
picture was taken.

It
was the perfect tool for the 2004 presidential campaign.

HANY
FARID: One of the most damaging political forgeries was the
image of John Kerry sharing a stage with Jane Fonda at an anti-war rally. So
this was when Senator Kerry was still trying to get the Democratic nomination
for President, and when this image broke, it made the headlines. People were
talking about it for weeks.

What
was interesting about that particular image is that when you look at it, you
can't tell that the lighting is different.

NEIL
deGRASSE TYSON: The photo looked
real, but when Hany used his light-direction tool, it revealed a completely
different story.

HANY
FARID: It was absolutely a fake. We were able to detect
differences in lighting between Jane Fonda and John Kerry by as much as a
thirty degrees difference.

NEIL
deGRASSE TYSON: Which means, once
again, this image was a combination of two photos.

Hany's
light-direction software could determine lighting in two dimensions. But he
wanted to find a way to work three-dimensionally. The key was in the eyes.

HANY
FARID: The eyes are a wonderful thing because they are a
partial mirror into the world in which you were photographed.

MICAH
JOHNSON: So we had this idea that you
could actually measure properties of the lighting environment from reflections
in somebody's eye.

HANY
FARID: If you look closely at my eyes, what you can
probably see is that there must be a light off to my right and slightly above. And
it's actually rectangular in shape. And you can see that because of where
the white is in my eyes. And you can probably see a reflection of that directly
in my eye.

NEIL
deGRASSE TYSON: Using the geometry
of the human eyeball, Hany developed a tool that exposed the position of the
subject and the light source in 3-D. Armed with his new eyeball software, he
was faced with this photo of the American Idol hosts.

HANY
FARID: The Associated Press was about to run this. And
there was something about the photograph that bothered all of us when we saw
it.

HANY
FARID: When we went in and looked at the eyes, we could
tell that the light in which each was photographed was completely different.

The
people who were photographed with two lights, we saw two dots on their eyes. For
the person with the flash, we saw a very small dot in the center of the eyes. And
for the other person, we saw a different shape and a different location. And so
it was radically different lighting in that case. And it was clearly a
composite of three photographs.

I
think, from the point of view of the Associated Press, this is not an
appropriate manipulation, and they just didn't publish the photograph.

NEIL
deGRASSE TYSON: In this digital
age, Hany's new technologies are indispensable. But developing a new
field of science is never an easy mission.

HANY
FARID: When I first got to Dartmouth, my post-doc advisor
said to me, "I don't think it'll work." And when
somebody who's a lot smarter than you says something's not going to
work, you better pay attention.

If
somebody tells me something won't work, I'm more determined than
ever to make it work.

NEIL
deGRASSE TYSON: Hany's strong
will started a long time ago, when he was a young boy growing up in Rochester,
New York.

HANY
FARID: I think my grades and my abilities in school were
either very good or very, very bad. And there was really nothing in between. There
are things that really resonate with me, and I will commit myself to it, and
there are other things that I find uninteresting, and I can't for the
life of me make it work. And I just couldn't really get myself to do the
work. I was in the slow lane a little bit.

My
mother called me one day when I was in college, and—I think I was a
junior at the time—I still didn't have a major. I was a C student. She'd
read an article in the Time Magazine
saying computer science is going to be big. She said, "You know, you
should think about taking a class." And I thought, "Yeah, right,
Mom." Like, what else would I say? But you know what? It sat with me, and
I ended up taking a class, and it was great. It was one of the first things I
was actually good at, and it changed my entire life.

Listen
to your mother!

NEIL
deGRASSE TYSON: In less than a
decade, Hany has taken his rule-breaking brand of computer science and
mathematics and helped pioneer the field of digital forensics. And he's
caught the attention of major players along the way.

Now
Adobe, developer of the software Photoshop, has invited Hany to work with them.

HANY
FARID: They were interested in collaborating with my lab at
Dartmouth, thinking about whether we can transfer that technology into software
that could actually be used by law enforcement, media outlets, scientific
publishers, to bring some of the techniques that we developed to a broader
audience.

NEIL
deGRASSE TYSON: Because of Adobe,
the use of Hany's software is likely to become widespread in the battle
against the forgers. Soon we may all know if what we're looking at is
real or fake.

KEVIN
O'CONNOR (Adobe): The research that Hany is doing is going to enable
people to continue believing in what they see.

NEIL
deGRASSE TYSON: So in the end, can
Hany win against the forgers?

HANY
FARID: I think the game of forensics is not you stop
forgeries. That's an unrealistic and naive goal. What it is is you make
it increasingly more difficult. I think, at the end the day, the average forger—the
fourteen-year-old, in Ohio, in his bedroom, making forgeries and posting them
on the web—they will lose. We will win that game. There is no doubt about
it. But if I wanted to play the other side, I will always be able to beat the
authentication game.

I'll
be able to create a fake, but you won't.

WISDOM OF THE CROWDS

NEIL
deGRASSE TYSON: In an election
year, people might disagree about who makes the best candidate, but you
don't hear much argument on the merits of democracy: that millions of
average people can, together, make a wise decision.

It
wasn't always so. In the early 20th century, this controversial
Englishman, Sir Francis Galton, tried to statistically test whether mobs of
common folk were capable of choosing well.

And,
as our musical correspondent Rob Morsberger tells us, what Sir Francis actually
found was that, mathematically, at least, there's often wisdom in a
crowd.

ROB
MORSBERGER (Correspondent): Sir Francis Galton was a nobleman

And
scorned the common masses.

He
thought that votes of governance

Should
be left to higher classes.

He'd
prove with all the data

From
a contest inescapable,

Of
guessing even simple things

That
commoners were incapable.

CARNIVAL
BARKER: Ladies and gentlemen, step right
up.

ROB MORSBERGER: What kind of contest
might it be?

CARNIVAL
BARKER: Guess the ox's weight and
see. Guess the weight correctly and win a prize!

LITTLE
BOY IN CROWD: It's 100!

ROB MORSBERGER: Said a little one.

ADULT
IN CROWD: That's much too light, at
least a ton.

ROB MORSBERGER: An eager crowd queued up to play,

Eight
hundred made a guess that day.

MATT
WINTERS: So he had 800 data
points.

CARNIVAL
BARKER: And now the ox's weight is
exactly...eleven hundred ninety-eight pounds. There are no winners!

MATT
WINTERS: It could maybe
be Wikipedia. You don't even need to be an expert, but if you know
something, then you're able to contribute, and that entry is able to be
that much more informed.

ROB MORSBERGER: Another sample of this fare...

JENNIFER
HILL: Who
wants to be a millionaire?

REGIS
PHILBINIMPERSONATOR: Yeah, the audience lifeline.

JENNIFER
HILL: If the
person feels like they can't answer the question by themself, ask the
audience.

KELLY
RADER: The
audience is right over 90 percent of the time.

JENNIFER
HILL: There
you go.

REGIS
PHILBIN IMPERSONATOR: How 'bout that, Gelman?

ANREW
GELMAN: The wrong Gelman...

REGIS
PHILBIN IMPERSONATOR: Sorry.

ROB MORSBERGER: One by one we're not too smart,

But
every guess it plays its part,

And
when you add them up you'll find...

ROB
MORSBERGER AND
CROWD: The wisdom of the crowd.

NEIL
deGRASSE TYSON: And now for some
final thoughts from the "dark side."

Consider
all we've learned about the size, age and contents of the universe, from
its fiery birth in the Big Bang, through 14 billion years of cosmic expansion
that has followed. Even better, consider the powerful laws of physics
we've discovered that account for it all. Kind of makes you stand with
pride for being human.

But
before you stand too tall, consider that, at this moment, we can account for
only about 15 percent of all the gravity we've ever measured in the
universe. We're simply clueless about what's causing the rest. Not
only that, if you add up all the matter and energy in the universe, it comes to
just four percent of all that drives cosmic expansion.

So
we're clueless about that one too, with no idea about what occupies the
remaining 96 percent.

We
call these two entities "dark matter" and "dark
energy." What are they? Maybe they're exotic never-before-seen
forms of matter and energy, or maybe they reveal a hidden flaw in our
understanding of how the universe works. But really, the two terms are
placeholders for our abject ignorance. We could just as easily have labeled
them "Bert" and "Ernie" or "Without-a-Clue
A" and "Without-a-Clue B."

So
we are left in a curious situation. What we know of the universe, we know well.
Yet a larger cosmic truth lies undiscovered before us, a humbling yet thrilling
prospect for the scientist driven not only by the search for answers, but by
the love of questions themselves.

And
that is the cosmic perspective.

And
now we'd like to hear your perspective on this episode of Nova
ScienceNOW. Log on to our Web site and tell us what you think. You can watch
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